Mixing tank for fibrous material suspended in liquid



July 14,.193G. J. c. F. c. RICHTER MIXING TANK FOR FIBROUS MATERIAL SUSPENDED IN LIQUID Filed Sept. 11, 1934 :1 r flung Patented July UNITED STATES "PATENT OFFICE MIXING TANK FOR FIBROUS MATERIAL SUSPENDED IN LIQUID Johan 'Cristofl'er'Fi-edrik Carl Richter, Oslo, Norway 7 Application September 11, 1934, Serial No. 743,567

' I In Norway July 8, 1933 is Claims. (on. sic-e7) The present invention relates to improvement in mixing tanks for fibrous material suspended in liquid and particularly has for its object to provide an improved mixing tank for suspended wood fibers and wood pulp, by means of which the variations in the consistency of the mass caused by varyingquality of the raw material or variations in the treatment in grinding plant, digesting plant or bleaching plant are equalized.

o A mixing tank for the purpose above specifiedmore, and they are generally made with concrete fairly concentrated pulp in. such tanks increasewith the depth of the tank, and special provisions must therefore be resorted to in order to obtain a satisfactory mixture. 5 In accordance with the present invention a satisfactory mixture of the suspension contained in mixing tanks of the type. specified is obtained by the cooperation of a mechanical circulation device, such as a circulation pump, with one or more guiding surfa'ces'or vanes arranged so as to form channels leading to the intake opening of the circulation device from different levels in the mixing tank, whereby it is obtained that mass from different levels of the mixing tank is conducted to the same circulation device, by-means of which an intimate mixture of the suspension from diiferent'levels is obtained.

Further features of the invention will be apparent from the following specification with referenceto the drawing, on which Figure 1 is a section on the line I-I oi'Figure 2,

Figure 2 is a section seen from above on the line II--II of Figure 1,

Figure 3 is aside view with parts in section on 'the line III-III of Figure 2.

The tank I, which may have a circular or other cross section, is divided by means of the vertical walls 2 and 3 in three chambers A1, B and A2,

which are in open communication with each other at C and D. Near the bottom of the mixingtank there'is locateda circulation device, for instance three mass pumps 4, 5 and 6, which are driven from theoutside in anysuitable manner and the h left hand end of chamber B. In the following chamber B will be termed the suction chamber and thechambers A1 and A2 will be termed the pressure chambers. The outlet openings of the pumps communicate with the pressure chambers, pumps d and 6 having their outlets directed laterally towards 8 and 9 in the chambers A1 and A2 respectively, whereas pump 5 mainly delivers in an upwardly direction into chamber ill,

which is in open communication with. pressure 10 chambers A1, A2. The pulp which may be taken for instance from digesters is introduced through tube E2. The level in the suction chamber is indicated at it. I

With the arrangement above specified the effect will be that the pumps would mostly take up mass from the bottom level, and a great deal of the contents of the mixing tank would take no part in the circulation and mixing operation.

This for example would be the case with all material above the dotted line it. v

In order to prevent stagnation of the material in the upper part of suction chamber B there is arranged in accordance with the invention one or more bamesor guiding vanes M, by means of which channels are formed extending from different levels of the suction chamber towards the pump intakes, which are all at the same level. Hereby the intake is divided in several sections, each of which acts on a different level of the suction chamber, so that the pumps are forced to take up material from all levels of the mixing tank and not only from the level in which the pump intakes are placed. Hereby it is obtained that even the part of the mass immediately above the intake openings adjacent wall I I will take part in the circulation and mixing process. I

After being thoroughly mixed in this manner the suspension in question is let out through some suitable device, such as outlet pipe l8.

In order to adapt the arrangement for varying levels in the mixing tank'the guiding vanes l4 may be adapted to be pivoted about their lower edges in order to place the upper edges at different levels or the vanes may be provided with openings controlled by valves or flaps as indicated at l'|..

In some cases it may also be advantageous to make the lower ends of guiding wanes I adjustable with regard to the intake openings of the circulation device in order to compound various grades of consistency in the upper or lower levels of the mixing tank, w

1 Although three' circulation pumps are illus:- trated on the drawing the principle may obvious- 1y also be adapted tor a single circulation pump,

' in which case the walls of suction chamber B will have to be' arranged as indicated by dotted lines 2', 3'.

I claim:

1. A mixing tank for suspended fibers and the like, comprising a mechanical circulation device having an intake opening, and a' plurality of guiding vanes for the mass associated with saidintake opening,. each vane extending to a position closely adjacent the running wheel or the circulation device, said guiding vanes being located so as to oi the circulation device to diflerent levels of the mixing tank to conduct masses from different levels of the mixing tank to the circulation device so that they may be mixed simultaneously therein. 2. A mixing tank for suspended fibers and the like comprising a device having an intake opening, consisting of at least two rotating pumps or impellers located adiacent each other at the same level and having intake openings, and a plurality v of guiding vanes for the mass associated with said intake openings and each vane extending to a position oloselyadjacent the running wheels of the said pump or impellers, said guiding vanes being located so as to form channels leading from the intake openings of the circulation devices to difierent levels of the mixing tank conduct masses from difierent levels of the mixing tank to the circulation devices so that they may be mixed simultaneously therein.

3. A mixing tank for suspended fibers and the like comprising a mechanical circulation device having an intake opening, and a plurality of guiding vanes for the mass associated with said intake opening, each vane extending to a position closely adjacent the running wheel of the circulation device, said guiding vanes being located so as to form channels leading from the intake opening of the circulation device to difierent levels of the mixing tank, said guiding vanes being adapted to be adjusted vertically at at least one end in order to regulate the supply of masses from different levels of the mixing tank to the circulation device so that they will be mixed simultaneously therein.

4. A mixing device for suspended fibers and the like, comprising a tank, at least two vertical walls in said tank defining between them a suction chamber, and each defining between itself and the tank a pressure chamber, a circulation device dis- 4 posed "atthe bottom 01' one end of the suction chamber and having an inlet-opening thereinto, and at least one vane extending upwardly from said inlet into said suction chamber, to guide masses of fibers from diilerent levels in the suction chamber simultaneously into the inlet, actuation of the circulation device drawing the masses through said suction chamber along the channels defined by said vane, through said circulation device into said pressure chambers, and back to the suction chamber.

I 5. A mixing device iorsuspended fibers and the like, comprising 'a tank, means in said tank defining a central suction chamber, and pressure chambers at each side thereof, a circulation device disposed at the bottom or and at one end ot'the suction chamber and .having an inlet opening "thereinto,:md at least one vane-extending up-' T wardly rrom said inlet into said suction chamber,-

to. guide masses of fibers iron diilerent levels in the suction chamber simultaneously into the inlet, said vane being adjustable, actuation of the.

circulation device drawing the from differspinach nels defined by said vane, through said circulation device into said pressure chambers, and back to the suction'chamber.

6. A mixing device for suspended fibers a id the like, comprising a tank, means in said tank defining a central suction chamber, and pressure chambers at each sidethereof, a circulation device disposed at the bottom of and at one end or the suction chamber and having an inlet opening thereinto, and at least one'vane extending upwardly from said inlet into said suction chamber, to guide masses of fibers from diilerent levels in the suction chamber simultaneously into the inlet, said vane being pivotal at its bottom end, adjacent the inlet, actuation of, the circulation device drawing the masses from different levels or the suction chamber along the channelsdefined by said vane, through said circulation device into said pressure chambers, and back to the suction chamber.

7. A mixing device for suspended fibers and the like, comprising a tank, means in said tank defining a central suction chamber, and pressure chambers at each side thereoi, a circulation device disposed at the bottom or and at one end of the suction chamber, and having an inlet opening thereinto, and at least one vane extending upwardly from said inlet into said suction chamher, to guide masses of fibers from different levels in the suction chamber simultaneously into the inlet, said vane being of two-pieces of unequal size, the short piece being pivoted to the long piece near the upper end of the vane, to provide for change of the levels of the masses from which are obtained the supply for the inlet, actuation of the circulation device drawing the masses from different levels of the suction chamber along the channels defined by said vane, through said circulation device into said pressure chambers, and back to the'suction chamber.

8. A mixing device iorsuspended fibers and the like, comprising a tank, means in said tank ,defining a central suction chamber, and pressure chambers at each side thereof, a circulation device disposed at the bottom oi! and at one end 01 the suction chamber and having an inlet opening thereinto, and at least one vane extending upwardly from said inlet into said suction chamber, to guide masses or fibers from different levels in the suction chamber simultaneously into the inlet, said vane having a valved opening near its upper,,outer end to provide for change of the levels of the masses from which are obtained the supply'tor the inlet, actuation of the circulation chambers at each side-thereof, a "circulation device disposed at the bottom of and at one end of the suction chamber and having an inlet opening thereinto, and at least one vane extending upwardlyirom said inlet into said suction chamber,

' to guide masses of fibers from diilerent levels in the suction chambersimultaneously into the inlet, said vane being adjustable at its bottom with respect to the inlet, so that control may be had over the relative quantity of masses from diflerent levels which are conducted to the inlet, actuation of the circulation device .the mm difierent levels of the suction chamber along the channels defined by said vane, throughsaid cir culation deviceinto said pressure chambers, and back-to the suction chamber.

10. A mixing device for suspended fibers and the like, comprising a tank, at least two vertical walls in said tank defining between them a suction' chamber, and each defining between itself and the ank a pressure chamber, at least two circulation devices placed side by side and' at approximately the same level at the bottom of one end of the suction chamber, and having inlets opening into said suction chamber, and at least one vane extending upwardly from said inlets.

intosaid suction chamber, to guide masses oi fibers from difierent levels in the suction chamber simultaneously into the inlet, the outlets of said circulation devices discharging one, into one pressure chamber, and another into the other pressure chamber, so that actuation of said circulation devices draws the masses through said suction chamber along the channels defined by said vane, through said circulation devices thence in two streams into said pressure chambers and then back into the suction chamber.

11. A mixing device for suspended fibers and the like, comprising a tank, at least two' vertical walls in said tank defining-between them a suction chamber, and each defining between itself and the tank a pressure chamber, at least two circulation devices placed side by side and at approximately the same level at the bottom of one end or the suction chamber, and ha opening into said suction chamber, the outlets of said circulation devices discharging, one into one pressure chamber, and another into the other pressure chamber, so that actuation of said circulation devices draws the masses through said suction chamber, through said circulation devices thencein two streams into said pressure chambers and then back into the suction chamber.

, 12, A mixing device for suspended fibers and the like, comprising a tank, at least two vertical depending from the top of inlets 3 walls in said tank'defining between them a suction chamber, and each defining between itself and the tank a pressure chamber, at least three circulation devices placed side by side and at approximately the same level at the bottom of one end or the suction chamber, and having inlets opening into said suction chamber, a vertical wall said tank through which the inlets of said circulation devices extend, and at least one vane extendingupwardly from said.iniets into said suction I masses oi fibers from difierent levels in the suction chamber simultaneously into the inlet, the outlets of the two end ones devices discharging, one into one pressure chamber and the other into the other pressure chamber, while the third circulation device discharges into the chamber. formed between the wall of the tank and said last-mentioned vertical wall, which chamber communicates directly with said preschamber, to guide oi the circulation sure chambers, so that actuation of said circulation devices draws the masses through said suction chamber along the channels defined by said vane, through said circulation devices,thence in divided streams into the pressure chambers, and then back into the suction chamber.

;13. A mixing tank for suspending fibers and the like, comprising a mechanical circulation deyice having an intake opening, and a plurality or guiding vanes for the mass, to a Position closely adjacent the running wheel 01' the circulation device and the intake opening therefor, the vanes each extending approximateis parallel to the direction of flow oi the corresponding one of the several streams defined by the vanes, so that the said vanes define substantially continuous paths for the mass from the difi'erent levels or the latter to said intake opening, whereby masses from difierent levels-oi the mixing tank are conducted to the circulation device where they are mined simultaneously together.

. JOHAN cnrs'roma ii'lmnmx cent. nrcH'rm:

each vane extending 30 

